Throughout a lifetime, bones and joints become damaged and worn through normal use and traumatic events. This degradation of the joints involving the articular cartilage and subchondral bone is known as arthritis and results in symptoms including joint pain, tenderness, stiffness, and potential locking of the joint.
Joint replacement arthroplasty is an orthopedic procedure in which the arthritic surface of the joint is replaced with a prosthetic component. It is considered the primary form of treatment to relieve joint pain or dysfunction that may limit mobility. During an arthroplasty procedure, the ends of the bone and articular cartilage are resurfaced (i.e., by cutting the bone) to match the backside of the implant.
The accurate placement and alignment of an implant is a large factor in determining the success of a joint arthroplasty procedure. A slight misalignment may result in poor wear characteristics, reduced functionality, and a decreased longevity.
In order to achieve accurate implant placement and alignment, one must accurately position the cutting tool vis-à-vis the bone prior to making any bone cuts. In some methods, a cutting jig may be used to accurately position and orient a cutting tool such as a saw, drill, or reamer. In other methods, the cuts may be made using a surgical assist device (e.g., a surgical robot) that controls a saw, cutter, or reamer. When a surgical assist device is used to make the cuts, the bone's position and orientation must be known precisely in three-dimensional space (and hence vis-à-vis the surgical assist device) to ensure that the cuts are made in the correct location. The current available methods of determining spatial orientation and location of a bone consist of registering the bones in a three-dimensional space, either using previously placed fiducial markers or by collecting or digitizing the locations of several points on the surface of the bone. The process using previously placed fiducial markers requires an additional surgical operation, and the process of digitizing points on the surface of the bone can be time consuming.
Thus, there is a need for a more efficient method for a surgeon to rapidly and accurately determine the spatial orientation and location of a bone during orthopedic surgery. This invention provides such a new and useful system and method.